Tank protected against overpressure

ABSTRACT

A tank capable of containing a liquid has a first volume ( 21 ) capable of containing the liquid ( 22 ), the first volume ( 21 ) having at least one opening ( 23 ) initially sealed by a first wall ( 24 ) and the first wall ( 24 ) being capable of being retracted when a pressure exerted thereon exceeds a specific threshold. The tank further has a second flexible wall ( 30 ), sealing said opening ( 23 ) in a sealed manner when the first wall ( 24 ) is retracted and capable of being deployed, via said opening ( 23 ), after the retraction of the first wall ( 24 ), in order to provide the liquid with a volume that is greater than the first volume ( 21 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to tanks and, in particular, fuel tanks protected against overpressure.

2. Description of the Related Art

Under normal conditions, a tank receives a liquid, such as a fuel. The problem proposed to be remedied here is for the liquid not to be spilled outside the tank in the event of significant overpressure. Where the tank is used on a land vehicle or aircraft, this corresponds, for example, to a high impact applied to the tank during a collision or a fall sustained by the vehicle or aircraft.

To achieve this, with reference to FIG. 1, it is known to produce a tank 10 which is capable of containing a liquid 12, comprising a first volume 11 capable of containing the liquid 12. Said first volume may comprise a plurality of service orifices, such as a filling orifice 17 or even a vent for exposure to the open air 18. This first volume 11 comprises at least one opening 13 which is initially sealed by a wall 14, as illustrated in FIG. 1. The wall 14 is capable of being retracted when a pressure exerted on said wall 14 exceeds a specific threshold (overpressure). FIG. 2 illustrates the state of the tank 10 after retraction of the wall 14. According to the prior art, a second volume 15 is generally provided in communication with the first volume 11 via said opening 13. Said second volume 15 is thus capable of receiving the excess liquid 16 which overflows from the first volume 11 via the opening 13, after retraction of the wall 14. Thus, the overpressure is reduced without the liquid spilling outside the tank 10. As a result, the retraction of the wall 14 at a selected location protects the remainder of the structure of the tank 10 against uncontrolled deterioration which may be produced by the effect of overpressure.

This approach presents several drawbacks. It is necessary for both the first volume 11 and the second volume 15, together with their connection point in the region of the opening 13, to be sealed relative to the liquid.

Moreover, a vent 19 has to be created in the second volume 15 in order to permit the air which is displaced by the excess liquid 16 to leave the tank 10, to permit the entry of this excess liquid 16. So that the liquid 16 does not flow through this vent 19, it is advisable to arrange said vent out of the range of gravity of said liquid 16, namely above said liquid. This may be difficult or even impossible to implement, in particular in the case of the tank 10 possibly being upturned. A further option consists in providing the vent 19 with an additional, and thus costly, valve device, selectively allowing the air but not the liquid 16 to pass through.

The present invention proposes a solution responding to the problem of containing the liquid, avoiding the aforementioned drawbacks.

SUMMARY OF THE INVENTION

The subject of the present invention is a tank capable of containing a liquid, comprising a first volume capable of containing said liquid, said first volume comprising at least one opening initially sealed by a first wall, said first wall being capable of being retracted when a pressure exerted thereon exceeds a specific threshold, said tank further comprising a second flexible wall, sealing said opening in a sealed manner when said first wall is retracted and capable of being deployed, in particular via said opening, after the retraction of the first wall, in order to provide the liquid with a volume which is greater than the first volume.

According to a feature of the invention, the second flexible wall forms part of a flexible casing capable of containing said liquid and capable of substantially following the internal shape of the first volume as long as the first wall is not retracted.

According to a further feature of the invention, the first volume is rigid.

According to a further feature of the invention, the tank comprises a second volume in communication with the first volume via said opening, capable of receiving said second flexible wall when deployed.

According to a further feature of the invention, the second volume is rigid.

According to a further feature of the invention, the retraction of the first wall is obtained by the rupture of said wall.

According to a further feature of the invention, the retraction of the first wall is obtained by the rupture of at least one fixing of said first wall.

According to a further feature of the invention, the second flexible wall is initially folded up before deployment, the deployment being obtained by unfolding.

According to a further feature of the invention, the second flexible wall is elastic, the deployment being obtained by elastic deformation.

According to a further feature of the invention, the second flexible wall and the flexible casing are made of a coated textile.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to particular embodiments provided solely by way of illustration and shown in the accompanying figures, in which:

FIGS. 1 and 2, already described, show in sectional view a tank according to the prior art, respectively before and after retraction of the first wall.

FIGS. 3 and 4 show in sectional view a tank according to the invention, respectively before and after retraction of the first wall.

FIGS. 5 and 6 detail two embodiments of the device for the retraction of the first wall.

FIG. 7 shows in sectional view a further embodiment of a tank according to the invention.

FIG. 8 shows in sectional view a further embodiment of a tank according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It goes without saying that the detailed description of the subject of the invention, provided solely by way of illustration, does not in any way limit the invention, technical equivalents also being included within the scope of the present invention.

Referring now to FIG. 3, a tank 20 capable of containing a liquid 22 is shown. As in the prior art, said tank 20 comprises a first volume 21 capable of containing the liquid 22. The first volume 21 comprises at least one opening 23 initially sealed by a wall 24, said wall 24 being capable of being retracted when a pressure exerted thereon exceeds a specific threshold.

According to a feature of the invention, the tank 20 further comprises a flexible casing 35 capable of containing said liquid 22 and capable of substantially following the internal shape of the first volume 21 as long as the wall 24 is not retracted. The flexible casing 35 is not necessarily fixed to the internal wall of the tank 20. By contrast, the flexible casing 35 has to have an orifice in the region of the orifice or each of the orifices present in the tank 20 such as an orifice 27 for filling with liquid, an orifice for use of the liquid (not shown) or even a vent 28 for exposure to the open air. In the region of each of these orifices 27, 28, the flexible casing 35 is fixed in a sealed manner to the tank 20 on the contour of the orifice 27, 28.

According to a main feature, said flexible casing 35 is capable of being deployed in the region of a zone 30, through the opening 23, after the retraction of the wall 24, in order to provide the liquid 22 with a volume greater than the first volume 21, thus avoiding overpressure. The additional liquid 26 flows out of the first volume 21 but remains contained in the deployed part of the flexible casing 35. During this deployment, the flexible casing 35 guarantees the containment of the liquid 22, 26.

In contrast to the first volume 11 according to the prior art which also provided the containing function and had to be sealed relative to the liquid 12, the first volume 21 according to the invention now only has a support function. It may thus be implemented by means of a flexible net, which is continuous or discontinuous.

According to a preferred embodiment, the first volume 21 is rigid in order to support the flexible casing 35 and the surplus liquid 26 and to provide the protection thereof against crushing. The first volume 21 may be discontinuous, no longer having a sealing function. This is illustrated by a dotted line in FIGS. 3, 4 and 7. It may also be continuous in order to provide the function of protection against perforation. This is illustrated by a continuous line in FIG. 8.

Depending on the stresses from which the tank 20 has to be protected, the tank 20 may be made of any material. Thus, it may be made of composite material such as plastics material or resin, either reinforced or not, or any other metal material.

According to the prior art, a second volume 15 is necessary to receive the surplus liquid 16. This is no longer necessary according to the invention, where the flexible casing 35, more specifically the zone 30, guarantees this receiving function with the necessary seal.

However, the tank 20 may comprise a second volume 25, adjacent to the first volume 21 in the region of said opening 23. Thus said second volume 25 may support the flexible casing 35 and the additional liquid 26 which it contains, when the zone 30 of the casing 35 is deployed through the opening 23.

Like the first volume 21, the second volume 25 only has the function of supporting and protecting the flexible casing 35. It may thus be flexible and/or discontinuous.

According to an advantageous feature, in order to protect the flexible casing 35 against crushing, the second volume 25 may be rigid.

It may also be advantageously discontinuous. The presence of multiple “holes” in the second volume 25 creates numerous vents for exposure to the open air, thus facilitating the deployment of said zone 30 of the flexible casing 35 permitting the outlet of air initially present in said second volume 25.

The second volume 25 may also advantageously be continuous in order to provide protection of the zone 30 of the flexible casing 35 against possible perforation. However, this continuity does not require a seal relative to the liquid.

In order to facilitate the deployment of the zone 30 of the flexible casing 35 via the opening 23, at least one vent 29 for exposure to the open air is necessary in the second volume 25. Advantageously relative to the prior art, such a vent 29 is implemented in a simplified manner by the invention. The orifice for such a vent 29 may be perforated at any point of the second volume 25, and does not have to be provided with any valve, since there is no risk of any flow of liquid, the seal being provided by the flexible casing 35. Thus, as shown in FIG. 8, such a vent 29 may be arranged at a low point, without the risk of liquid flowing out.

The retractable wall 24 may be produced in different ways. Thus it may be created by a weakened wall, so that it may be broken. The weakening may follow a contour line along the opening 23 or may even comprise lines which are transverse to said opening 23. This is illustrated in FIG. 5, where a line/zone 33 is weakened between two elements 31, 32.

The retractable wall 24 may also be produced, as illustrated in FIG. 6, by means of a part attached 32 to a part 31, sealing the opening 23 and fixed by means of at least one weakened fixing 34. The rupture of said fixing 34 creates the retraction.

The retractable wall 24 may also be produced by means of an articulated gate, sealed by a weakened latching device.

The person skilled in the art will know how to determine other embodiments from the illustrated examples.

According to a first embodiment, illustrated in FIG. 3, the zone 30 of the flexible casing 35 is initially folded up before deployment. The deployment is thus obtained by unfolding the zone 30 of the flexible casing 35. In this case, the flexible casing 35 may be made of a material which has very little capacity for deformation or is not deformable. Advantageously, the zone 30 of the flexible casing 35 intended to be deployed outside the first volume 21 may be preformed to follow a selected shape, for example the shape of a possible second volume 25.

According to a second embodiment, the zone 30 of the flexible casing 35 is made so as to be elastic. In this case, the deployment and the reduction in pressure which accompanies said deployment are obtained by elastic deformation of said zone 30 of the flexible casing 35.

The flexible casing 35 and its zone 30 may be produced from any material which is sufficiently flexible to be subjected to the stresses of deployment, whilst ensuring the seal relative to the liquid.

Depending on the liquid contained, there may be additional stresses, in particular chemical stresses.

In the case of the use of fuel, the flexible casing 35 is advantageously made of coated textile. The textile may thus be a woven fabric or not. The coating is produced, for example, using an elastomer of the rubber type.

Various modifications may be made to the embodiment described above, without otherwise departing from the scope of the invention.

Thus, for example, the flexible casing 35 could be omitted to a large extent, to leave just the zone 30, said zone being fixed in a sealed manner on the contour of the opening 23. 

1. A tank capable of containing a liquid, comprising a first volume (21) capable of containing said liquid (22), said first volume (21) comprising at least one opening (23) initially sealed by a first wall (24), said first wall (24) being capable of being retracted when a pressure exerted thereon exceeds a specific threshold, characterized in that the tank comprises a second flexible wall (30), sealing said opening (23) in a sealed manner when the first wall (24) is retracted and capable of being deployed, via said opening (23), after the retraction of said first wall (24), in order to provide the liquid with a volume that is greater than the first volume (21).
 2. The tank of claim 1, where said second flexible wall (30) forms part of a flexible casing (35) capable of containing said liquid (22) and capable of substantially following the internal shape of the first volume (21) as long as the first wall (24) is not retracted.
 3. The tank of claim 2, where the first volume (21) is rigid.
 4. The tank of claim 1, comprising a second volume (25) in communication with the first volume (21) via said opening (23), capable of receiving said second flexible wall (35) when deployed.
 5. The tank of claim 4, where the second volume is rigid (25).
 6. The tank of claim 1, where the retraction of the first wall (24) is obtained by rupture of the first wall (24).
 7. The tank of claim 1, where the retraction of the first wall (24) is obtained by the rupture of at least one fixing (34) of said first wall (24).
 8. The tank of claim 1, where the second flexible wall (30) is initially folded up before deployment, the deployment being obtained by unfolding.
 9. The tank of claim 1, where the second flexible wall (30) is elastic, the deployment being obtained by elastic deformation.
 10. The tank of claim 1, where the second flexible wall (30) and the flexible casing (35) are made of a coated textile. 